1. Field of the Invention
The present invention relates to an amplifying photoelectric conversion apparatus.
2. Description of the Related Art
As photoelectric conversion apparatuses have come to have a larger number of pixels in recent years, pixels have become smaller or finer. When pixels become finer, because the amount of light that enters each pixel is decreased, sensitivity is decreased and image quality is deteriorated in the apparatuses.
Japanese Patent Laid-Open No. 2001-053260 discloses a configuration of a photoelectric conversion apparatus in which a photoelectric conversion unit is formed in an N-type semiconductor region surrounded by a P-type semiconductor region, thereby improving sensitivity.
Japanese Patent Laid-Open No. 2005-142251 discloses a configuration in which a contact is provided for each pixel as means for suppressing shading due to variations in the well potential of the pixel. By providing a contact for each pixel, it is not necessary to allocate a place in which a contact is to be arranged in a chip, making it possible to suppress increasing the chip area, and making it possible to suppress shading without disturbing pixel arrangement pitches.
In the pixel structure disclosed in Japanese Patent Laid-Open No. 2001-053260, there is also a case in which signals from pixels may vary due to variations in the well potential for each pixel. However, studies have not been sufficiently made on variations in the well potential in such a pixel structure.